[tacotime]

Maybe something like Chia (chia.net) that "farms" from pre-computed "plots" as proof of work? There is still an energy intensive cost to the initial plot creation phase, but it is soon amortized by the low cost farming phase, where the precomputed proofs begin to do their work. As SSD storage is expected to become less $/TB than HDD storage in about 5 years, this could make for a very energy efficient PoW scheme.

I don't understand enough to know if it's a design decision or a technological limitation but the barrier to entry for something like chia also seems much lower, hopefully democratizing the ability to participate in the creation/validation side of the network. Chia requires a single ~100GB plot file (and 332 GiB scratch space when creating the plot) to start farming, which is a pretty low bar. I don't have to buy an expensive special purpose bitcoin ASIC and I don't have to stake the equivalent of 68,416.96 United States Dollar (32 eth) to get started and start contributing.